After repairing disk permissions three times in immediate succession, there is still a long list of repaired items when it's finished, most beginning with "ACL found but not expected," with many of these in iTunes.
Any ideas on what's happening? I was expecting an empty box when all were repaired.
I have heard it said the Disk Permissions is useless. Yes? No?
Yes! Repairing disk permissions is useless. It's a holdover from the days when people would install OS X just to dip their toes into, but would run back to the comforting familiarity of MacOS 9.x (or earlier) to do "real" work. MacOS had absolutely no concept of UNIX permissions, would ignore any permissions that OS X had set on a file, and would erase permissions from any file it created. DURP (Disk Utility: Repair Permissions) was never anything more than a clumsy attempt to repair at least some of the damage that MacOS would do to an OS X installation.
It has not gotten significantly less clumsy over the years. What little reason it had for existing in the first place is ancient history.
One clumsiness it has always exhibited is that it thinks the "correct" permissions are those listed in the compressed archive from which an installer package extracts the files. A compressed archive cannot specify an ACL; there's no provision for that in the file format. Instead, the package includes post-installation scripts (also extracted from the compressed archive) that run after the archive is expanded, and can do anything a shell script can do. In particular, a post-installation script can apply ACLs to the newly installed files (or even to files/folders that had previously been installed from other packages).
Those ACLs belong there, but since they weren't mentioned in the compressed archive itself, DURP thinks they're erroneous. It complains about them, but doesn't know how to remove them, so it leaves them in place where they can be complained about on the next run.
You can save yourself a fair amount of wasted computer time, and a great deal of mental aggravation, if you just stop running DURP. It is a complete and utter waste of time. The "errors" it reports are not errors. The "fixes" it claims to apply are unnecessary, often incorrect, and rarely actually applied.